Initial screening of antigen specific IgG in human plasma pools.
Total IgG specific for each of the 21 antigens was measured by ELISA in three plasma pools (10–12 donors in each pool). Bars represent geometric means of the EC50 calculated by a sigmoidal fitting of data points from a 10-fold plasma dilution series. Responses under 1 or too low for accurate fitting were adjusted to EC50 = 1. Grey bars indicate the antigens that were selected for IgG responder frequency analysis in individual donors.